Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Keeping an eye on the future upcoming demands for mobile applications, 3GPP has the target to enhance the downlink packet data rate in many folds. As a result, WCDMA specifications have been evolved with the addition of a new feature called HSDPA (High Speed Downlink Packet Access) in Release 5. The goal of HSDPA has been to increase the system capacity by increasing the data rate and reduce the round trip delay. The increase of system capacity has been achieved by dynamic sharing of code resource and certain amount of power.
A number of research papers have shown that HSDPA will enhance WCDMA system with the fulfillment of the above objective. As per the business forcast, HSDPA will start getting deployed towards the end of this year (2005). Howe ver, in a real deployment scenario, it may happen that some of the cells are implemented with HSDPA and some are not yet; what will happen to the capaci ty of those cells without HSDPA? When HSDPA is implemented in a cell, the base station uses more power, imparting more interference to the neighbouring cells, thus affecting their dedicated channel capacity. In addition to the higher power, if the availability of data in the HSDPA channel varies, then the interf erence to the neighbouring cell might be larger and °uctuating, in turn, the dedicated channel capacity of the neighbouring cells might be affected.
This scenario has been studied in this master thesis. Mainly, it has been studied how is the dedicated channel capacity of a cell without HSDPA affected by the introduction of an HSDPA channel in adjacent cell. Does this influence depend on the data traffic on the HSDPA channel?
With the simple system model used, it has been observed that though there is a change in the capacity of the system after implementing HSDPA in adjacent cells, the variation is negligible. It has been found that the decrease in the dedicated channel capacity is more if the HSDPA data traffic is larger. The fluctuating data in HSDPA channel has not degraded the capacity further; it is only the higher power, which has affected the dedicated channel capacity. However, in all these cases, variation can be considered as negligible. So, it has been concluded that there is no impact on the capacity of cells which are not with HSDPA after implementing HSDPA in adjacent cells. Considering the limitations in this study, it has been suggested to study this aspect further by using a more complex system model to find out the reality.